The goal of this project is the development of innovative ultrasonic technology and commercial devices to increase efficiency of hemodialysis performed with existing dialysis machines, dialyzers and clinical protocols. This will enable more efficacious or possibly shorter dialysis treatments. Specific aims for Phase I are to fully characterize ultrasonic enhancement of flux in standard hollow fiber dialyzers with emphasis on that of phosphorous, to make a preliminary assessment of the safety of the ultrasound required on human blood, and to formulate a preliminary device design for prototyping in Phase II. Dialyzers will be placed in a testbed containing an ultrasonically insonified water bath. A blood substitute of saline spiked with urea, vitamin B-12 and sodium phosphate will be dialyzed over a range of acoustic frequencies and amplitudes. "Blood out" concentrations will be sampled periodically to measure clearance and total solute removal. Dialyzers will then be tested for reuse. Ultrasound regimes found effective without damaging dialyzers will be incorporated into a preliminary device design. Small blood samples will be exposed to ultrasound in these regimes to explore safety. Phase I data will be relevant to further study of dialysis kinetics of phosphorous and to ultrasonic enhancement of diffusion in general. PROPOSED COMMERCIAL APPLICATIONS: The flux enhancement device to be developed in this project will be compatible with existing dialysis equipment without modification. Its use would entail merely inserting a dialyzer - with the usual lines attached - into the device instead of the usual clamp on the side of the dialysis machine. This approach should simplify regulatory acceptance and make it attractive to hospitals and dialysis units. The device itself will be very simple (similar to an ultrasonic cleaner), relatively inexpensive (with price on the order of $3000 $5000) and easy to operate and maintain. An annual market of 10,000 units worldwide may be possible.